A double action pistol comprises among others a barrel with a breech at the rear end; a slide also known as breech block and bearing a firing pin; a trigger with associated trigger bar, sear and interruptor; a spring-loaded hammer; a magazine within a magazine chamber and a safety mechanism. During operation the slide slides back and forth between an advanced, firing position and a rear, cocked position. The forward movement is brought about by the expansion of so-called recoil springs which occurs when the trigger is pulled, and during this movement the slide strips a cartridge from the magazine and inserts it into the breech whereupon the hammer strikes the firing pin and the cartridge is fired. Upon firing, the propellant gas pressure pushes the slide rearwards whereby the recoil springs are compressed, the hammer is cocked and the pistol is ready for another firing round.
The magazine holds a limited number of ammunition rounds, say fifteen, and when in the course of operation the magazine is emptied it has to be replaced by a new, loaded one.
When the pistol has to be cocked manually by pulling the slide rearwards, the hammer is eccentrically tilted to the rear, thereby compressing the spring with which it is associated and thus creating a bias that upon release urges the hammer to swing forward and strike the firing pin inside the slide. As long as the trigger is not pulled, the sear locks the hammer in the cocked position. When the trigger is pulled, the rearward moving trigger bar pushes the sear out of engagement with the hammer whereupon the latter is released and strikes the firing pin.
In practice, it very often happens that in anticipation of a pistol shooting event a combatant cocks his pistol and switches the safety catch from the safe to the firing position. This, however, creates a dangerous situation in that any accidental shock or impact may release the hammer and cause the pistol to be fired. It is possible to cope with such a situation by manually decocking the hammer in guiding it gently into the forward position without allowing it to strike the firing pin. When now the trigger is pulled, the trigger bar will in a first phase, in collaboration with the sear and interruptor, recock the hammer. By further pulling the trigger it will, in a second phase, bring about the release of the hammer so that the latter may forcibly strike the firing pin, thereby triggering off the firing and subsequent recoiling operation.
In order to avoid the need for manual decocking, some double action pistols are provided with mechanical decocking mechanisms.
Decocking of a state of the art double action type pistol brings about the expansion of the compression spring associated with the hammer with the consequence that during the trigger pull phase at which the hammer is recocked, it is necessary to exert sufficient force for the recompression of the compression spring associated with the hammer. Depending on the type of pistol, a complete trigger pull may require the exertion of a force of the order of 6-10 kg, of which the first phase trigger pull accounts only for about 2-3 kg. Thus, where in a manually cocked conventional double-action pistol the hammer is decocked, the performance of the first shot requires the exertion of a substantial force. Apart from the intrinsic inconvenience, such exertion of force may and usually does cause inaccurate firing which, when bearing in mind that the first shot is very often the most critical, may have fatal consequences.
It is thus the object of the present invention to provide a double action pistol with a decocking mechanism as known per se, having an improved trigger mechanism by which the force that has to be exerted for firing the pistol from a decocked state is significantly smaller than with state of the art double action pistols.